June 18, 2007

The author of This Is Your Brain on Music is perfectly poised to write a book about the neuroscience of music. Daniel J Levitin began his career as a musician and sound engineer, and later he passed into academia to better grasp the science behind music’s appeal. His dual interests, music and neuroscience, and their interplay seem to appeal to many others, as evidenced by the book’s ubiquity in like-minded media outlets over the last few months. (Try here.) This likely also reflects the fact that he has written a book comprehensible to those without any music or science training.

The book does not present a cohesive theory for how music is processed in the brain, in part because there isn’t one. Levitin’s fragmentary approach reflects the fragmentary nature of the field. But even the fragments are intriguing. Music first activates the auditory cortex. Then areas adjacent and overlapping with Broca’s interpret musical syntax. Finally the meaning of the music (the musical semantics) is delineated in the mesolimbic system, including regions near Wernicke’s area. This is hardly the whole story. The cerebellum (10% of brain weight; 50-80% of neurons) possesses direct connections from the ear. Through its connections to the basal ganglia it is implicated in rhythm and meter. How all these linkages are coordinated into the experience of music is less clear, but Levitin surely puts many of the pieces on the table.

Levitin introduces a few diseases that offer insights into the neuroscience of music. Those with higher functioning autistism are drawn to the structure of music but they miss the emotional appeal. Perhaps this is a result of their smaller neocerebellums. On the other hand, people with Williams Syndrome have larger neocerebellums and are musically gifted. Levitin casts his net wider still. Citing work done by Schmahmann et al regarding the cerebellar cognitive affective syndromes, he associates socialibility and musicality.

In later chapters, Levitin takes a more psychological approach as he explores the genesis of musical preference and the nature of expertise. In the last chapter he dives into evolutionary psychology. Where this fits into the overarching purpose of the book is not clear. Levitin supports the idea that music, or traits that endow musical ability are present today as a result of sexual selection. Here is not the place to deconstruct each of his arguments for this position. This has been done by many critics of evolutionary psychology. What is more interesting is why intelligent thinkers insist that certain traits exist as the consequence of selection, either sexual or natural. Perhaps the mantle of natural selection bestows prestige and lends credence to an area of research. Regardless, the evolution of music and musical ability as the result of sexual selection is unprovable, and moreover, it does little to advance our understanding of why some music sounds so good.